Felt guide for pulp and paper machines and the like



. F. FORD. FELT GUIDE FOR PULP AND PAPER MACHINES AND THE LIKE.

APPLICATION FILED MAR. 8, 1920.

Patented May 2, 1922.

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Franc/I9 Ford FRANCIS roan, orjisnonrronvrnnn, QUEBEC, CANADA.

FELT GUIDE FOR PULP .AND PAPER MACHINES AND THE LIKE.

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Specification of Letters Patent.

Patented May 2, 1922.

hpplication'filedl llarch 8, 1920. Serial No.'364=,051.

.scription.

This invention relates to .improvements in guiding means for elements otbelt form and particularly for the felts of pulp or paper machines.

The object ofthe invention is to provide ,meansfor automatically guiding a felt or.

other element of belt form, whereby it will be returned to proper position on the rolls over which it runs in the event of anytend- 'ency to :run off the ends of such rolls.

A "further object is to provide guiding means which are simple, inexpensive, du-- rable and efficient and which may be relied upon to operate satisfactorily with a minimum of attention and with practically no operating expense.

The device briefly described comprises a suction box in contact with the running element'anda suction line connected to said boxand including a water columnyat the bottom of which is a reciprocatable memberrthe position of which 'is controlled by fluctuations in the eilective weight of the column due .tofiuctuations of pressure in the suction line. This reciprocatable. member is arranged to regulate the angular relation between the running element and a supporting roll,

' whereby the runningelement may be caused to creep edgewise upon the roll to correct any edgewise displacement.

In the drawings which illustrate the invention;

Fig. 1 is a side elevation of the device practically covered by the element 152 as prepartly in section.

Fig. 2 isa plan view thereof.

Referring more particularly to the drawings, 1'1 designates the various rolls of a machine such as a pulp or paper machine. over which travels a moving element 12 0t belt form such as a felt. Atany suitable point, an idle roll '13 is provided in sufficient contact with the element 12 to be revolved thereby. One end of this roll is journalled in a'bearing 14 pivotally-mounted in a preferably rigid bracket or frame member 15, whereby the roll may be oscillated in the plane of'movement 'ofthat part ofthe-element with which the rollcontacts. The opposite end 10f :theroll is journalled in a bearing 16 carried by an arm '17- pivotallysupported from a preferably rigid bracket or frame part '18, in such a manner "that the freecen'd of the arm may swing and move "the roll in a plane substantially parallel with the Plane of movement of that :part of the element with which the roll engages. The arm 17 has connected thereto .a second-arm 19, the two arms constituting in the 'form illustrated a 'bell'cra-nk lever, one extremity of which carries the roll 13. The "free extremity of the arm '19, that is to say, the

remaining end of the bell crank lever, is connectedby a link 20 with a block Ql-adjustably mounted on a rod 22; one end of which is-gu'ided in any suitable support such as the member 18.

The opposite'end-of this rod 22 is connected to a flexible diaphragm 23 of leather or other suitable material forming the top and closure member of a vessel 24. The interior of this vessel 24 is substantially at the level of and in communication with the bottom of a flask or standpipe 25-which'is'closedat itsupper end. A suction box 26 is provided at any suitable point in communication with the element 12 and is provided with a short "air inletslot 27 disposed to be normally partly covered by'the element 19,. A suction pipe 28 leads from the bottom of the suction box to the top of the flask A. second suction pipe 29 leads from the top of the flask 25 toany suitable vacuum producing apparatus. This pipe may be provided if desired with a valve '30 for severing communication between the suction apparatus and theflaslz.

The slot of the suction box isnormally viously stated and the roll 13 normally extends exactly at rightangles to'the direction of movement of the element. The vessel 24 and the flask 25 are preferably filled with.-

capacity of the vacuum apparatus, so that there is. normally. apartial vacuum in the flask above the wate column, with the result that air pressure on the diaphragm 23 Supports part of the weight of the column of water. If the element 12 should creep laterally on its supporting rolls 11, it will either decrease or increase the amount of slot 27 uncovered and will thereby vary the amount of vacuum above the water column. If the uncovered portion of the slot is increased, the greater inertia of air reduces the vacuum in the flask 25, so that more than the weight of water column is thrown upon the diaphragm 23 and the diaphragm is thereby bulged upwardly and shifts the rod 22. The rod movement is communicated through the link 20 and arm 19 to the arm 17, so that the roll is swung out of its exact transverse relation with the element 12. It is well known that a belt tends always to travel at right angles to the axis of a supporting roll and that, asaresult of this tendency, a belt will creep edgewise on a sup porting roll in an. endeavor to find a position in which it will travel exactly at right angles to the axis of the roll. As soon as the roll is shifted, the element 12 commences to creep edgewise thereon and is thus returned to its proper relation with the suction slot 27 As the exposed area of the slot 27 gradually decreases, the vacuum effective above the water column increases, so that air pressure on the diaphragm 23 causes a gradual movement of the same to restore the parts to their original positions. In this Way, the correcting influence is proportional to the amount of lateral displacement of the element 12, so that there is no tendency for the correction to be exaggerated and produce a second displacement opposite to the first. If the lateral displacement of the element 12 should produce a reduction of the exposed portion of the slot 27, the inrush of air will obviously be decreased and the vacuum above the water column increased, with the result that air pressure on the diaphragm 23 will depress the same and produce an angular displacement of the roll 13 opposite to that previously described,

From the foregoing description, it will be readily seen that the device is extremely simple, durable and inexpensive in its construction and includes no parts liable to get out of order. The form illustrated is designed with special reference to pulp and paper machines where constant pressure suction apparatus is already installed. The amount of air flowing through the device is at no time very great, so that no increase of power is required to produce the desired vacuum. When the device is installed on a pulp or other wet machine, the device will automatically keep itself supplied with water which will be drawn from the element 12 through the covered portion of the slot 27 into the flask 25, Any excess of water will flow away through the suction pipe 29 and may be discharged through the vacuum apparatus or through a suitable trap. When the device is in use on a dry machine, the water lost by evaporation should be replaced from time to time to ensure an effective height of water column.

While the parts of the device have been shown in a certain specific relation, it will be understood that this relation may be altered as desired without departing from the spirit of the invention. Obviously, the diaphragm is merely the equivalent of a piston and may be replaced by a piston of sufficient area without altering in any way the principle or operation of the device. The use of the diaphragm is, however, preferred as it has the more simple and less expensive construction and also eliminates friction and leakage losses. It will also be understood that the invention will function quite as well if the pressures maintained over the water column are super-atmospheric instead of sub-atmospheric.

Having thus described my invention, what if claim is 1. in a device of the class described, a guide roll adapted to engage an element to be regulated, adjustable supporting mechanism for said roll including a reciprocating member, a water column arranged to reciprocate said member, and means for varying air pressure above said column including a conduit having an opening to the atmosphere located to be normally partly covered by an element to be regulated.

2. A felt strip mounted on rolls, an adusting roll for maintaining said strip on said rolls, a hydraulic machine having a standing water column operatively' connected to said adjusting roll and a vacuum member in operative engagement with said fluid pressure member and regulated by the felt strip in passage taereon.

8. A felt strip mounted on rolls, an oscillating roll for maintaining said strip on said rolls, a hydraulic machine oscillating said roll and a vacuum box having an opening normally covered by said strip andconnective mechanism controlled thereby for changing the pressure in said hydraulic ma chine in the displacement of the strip.

4. A felt strip mounted on rolls, an adjusting roll for maintaining said strip on said rolls, a fluid pressure formed of a vesreciprocated by said diaphragm and a vacuum member aotuative said fluid presciprocated by said diaphragm and a vacuum sure member and regulated by the felt. member aetuative said fluid pressure mem- 6. A felt strip mounted on rolls, an adber and regulated by the felt strip in pas- 10 justing roll for maintaining said strip on sage thereon. said rolls, a fluid pressure, a post and levers In Witness whereof, I have hereunto set operative by said diaphragm and operatively my hand. connected to said adjusting roll, a lever re- FRANCIS FORD. 

